“The MerVal continues moving in the same line (as Wall Street) through Tenaris and Brazil’s Petrobras, which are the only shares being traded at bigger volumes,” said Antonio Cejuela, an analyst at Puente Hermanos brokerage.

Shares of index heavyweight Tenaris (TENA.BA), which makes steel tubes for the energy industry, fell 1.13 percent to 35.00 pesos. Brazilian energy company Petrobras (APBR.BA) lost 0.57 percent to end at 43.40 pesos a share.

These two companies account for 46 percent of the MerVal’s weighting and often move along with U.S. crude futures, which ultimately ended higher after a late bounce.

Argentine government bonds traded over the counter in Buenos Aires fell 0.3 percent on average, led by the dollar-denominated Boden 2014, which sank 5 percent to an ask price of 11.40 ARBODEN14D=RASL.

Investors are awaiting an imminent debt exchange involving bank loans known as “guaranteed loans,” which date from the 2001-2002 economic crisis and largely mature in the next few years. Banking sources say they will be swapped for a new, five-year bond denominated in pesos.

On the foreign exchange market, the peso weakened against the dollar as the central bank bulked up its foreign reserves by buying greenbacks, traders said.

In formal exchange between banks, where the central bank intervenes nearly every day, the peso slipped 0.07 percent to 3.4725/3.4750 per dollar ARS=RASL.